// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include "cpptypehierarchy.h"

#include "cppeditorconstants.h"
#include "cppeditordocument.h"
#include "cppeditortr.h"
#include "cppeditorwidget.h"
#include "cppelementevaluator.h"

#include <coreplugin/actionmanager/actionmanager.h>
#include <coreplugin/editormanager/editormanager.h>
#include <coreplugin/find/itemviewfind.h>
#include <coreplugin/progressmanager/progressmanager.h>

#include <texteditor/texteditor.h>
#include <texteditor/typehierarchy.h>

#include <utils/algorithm.h>
#include <utils/delegates.h>
#include <utils/dropsupport.h>
#include <utils/futuresynchronizer.h>
#include <utils/navigationtreeview.h>
#include <utils/progressindicator.h>

#include <QFuture>
#include <QFutureWatcher>
#include <QLabel>
#include <QMenu>
#include <QModelIndex>
#include <QStackedLayout>
#include <QStandardItemModel>
#include <QVBoxLayout>

using namespace Core;
using namespace Utils;

namespace CppEditor::Internal {

class CppClass;
class CppElement;

class CppTypeHierarchyModel : public QStandardItemModel
{
public:
    CppTypeHierarchyModel(QObject *parent)
        : QStandardItemModel(parent)
    {}

    Qt::DropActions supportedDragActions() const override;
    QStringList mimeTypes() const override;
    QMimeData *mimeData(const QModelIndexList &indexes) const override;
};

class CppTypeHierarchyWidget : public TextEditor::TypeHierarchyWidget
{
public:
    CppTypeHierarchyWidget();

    void perform();

private:
    void reload() override { perform(); }

    void displayHierarchy();
    typedef QList<CppClass> CppClass::*HierarchyMember;
    void performFromExpression(const QString &expression, const FilePath &filePath);
    QStandardItem *buildHierarchy(const CppClass &cppClass, QStandardItem *parent,
                                  bool isRoot, HierarchyMember member);
    void showNoTypeHierarchyLabel();
    void showTypeHierarchy();
    void showProgress();
    void hideProgress();
    void clearTypeHierarchy();
    void onItemActivated(const QModelIndex &index);
    void onItemDoubleClicked(const QModelIndex &index);

    NavigationTreeView *m_treeView = nullptr;
    QWidget *m_hierarchyWidget = nullptr;
    QStackedLayout *m_stackLayout = nullptr;
    QStandardItemModel *m_model = nullptr;
    AnnotatedItemDelegate *m_delegate = nullptr;
    TextEditor::TextEditorLinkLabel *m_inspectedClass = nullptr;
    QLabel *m_infoLabel = nullptr;
    QFuture<std::shared_ptr<CppElement>> m_future;
    QFutureWatcher<void> m_futureWatcher;
    FutureSynchronizer m_synchronizer;
    ProgressIndicator *m_progressIndicator = nullptr;
    QString m_oldClass;
    bool m_showOldClass = false;
    int m_runningIndexers = 0;
};

enum ItemRole {
    AnnotationRole = Qt::UserRole + 1,
    LinkRole
};

QStandardItem *itemForClass(const CppClass &cppClass)
{
    auto item = new QStandardItem;
    item->setFlags(item->flags() | Qt::ItemIsDragEnabled);
    item->setData(cppClass.name, Qt::DisplayRole);
    if (cppClass.name != cppClass.qualifiedName)
        item->setData(cppClass.qualifiedName, AnnotationRole);
    item->setData(iconForType(cppClass.iconType), Qt::DecorationRole);
    QVariant link;
    link.setValue(Link(cppClass.link));
    item->setData(link, LinkRole);
    return item;
}

QList<CppClass> sortClasses(const QList<CppClass> &cppClasses)
{
    return sorted(cppClasses, [](const CppClass &c1, const CppClass &c2) -> bool {
        const QString key1 = c1.name + QLatin1String("::") + c1.qualifiedName;
        const QString key2 = c2.name + QLatin1String("::") + c2.qualifiedName;
        return key1 < key2;
    });
}

class CppTypeHierarchyTreeView : public NavigationTreeView
{
public:
    CppTypeHierarchyTreeView(QWidget *parent)
        : NavigationTreeView(parent)
    {}

    void contextMenuEvent(QContextMenuEvent *event) override
    {
        if (!event)
            return;

        QMenu contextMenu;

        QAction *action = contextMenu.addAction(Tr::tr("Open in Editor"));
        connect(action, &QAction::triggered, this, [this] () {
            emit activated(currentIndex());
        });
        action = contextMenu.addAction(Tr::tr("Open Type Hierarchy"));
        connect(action, &QAction::triggered, this, [this] () {
            emit doubleClicked(currentIndex());
        });

        contextMenu.addSeparator();

        action = contextMenu.addAction(Tr::tr("Expand All"));
        connect(action, &QAction::triggered, this, &QTreeView::expandAll);
        action = contextMenu.addAction(Tr::tr("Collapse All"));
        connect(action, &QAction::triggered, this, &QTreeView::collapseAll);

        contextMenu.exec(event->globalPos());

        event->accept();
    }
};

// CppTypeHierarchyWidget

CppTypeHierarchyWidget::CppTypeHierarchyWidget()
{
    m_inspectedClass = new TextEditor::TextEditorLinkLabel(this);
    m_inspectedClass->setContentsMargins(5, 5, 5, 5);
    m_model = new CppTypeHierarchyModel(this);
    m_treeView = new CppTypeHierarchyTreeView(this);
    m_treeView->setActivationMode(SingleClickActivation);
    m_delegate = new AnnotatedItemDelegate(this);
    m_delegate->setDelimiter(QLatin1String(" "));
    m_delegate->setAnnotationRole(AnnotationRole);
    m_treeView->setModel(m_model);
    m_treeView->setExpandsOnDoubleClick(false);
    m_treeView->setEditTriggers(QAbstractItemView::NoEditTriggers);
    m_treeView->setItemDelegate(m_delegate);
    m_treeView->setRootIsDecorated(false);
    m_treeView->setDragEnabled(true);
    m_treeView->setDragDropMode(QAbstractItemView::DragOnly);
    m_treeView->setDefaultDropAction(Qt::MoveAction);
    connect(m_treeView, &QTreeView::activated, this, &CppTypeHierarchyWidget::onItemActivated);
    connect(m_treeView, &QTreeView::doubleClicked, this, &CppTypeHierarchyWidget::onItemDoubleClicked);

    m_infoLabel = new QLabel(this);
    m_infoLabel->setAlignment(Qt::AlignCenter);
    m_infoLabel->setAutoFillBackground(true);
    m_infoLabel->setBackgroundRole(QPalette::Base);

    m_hierarchyWidget = new QWidget(this);
    auto layout = new QVBoxLayout;
    layout->setContentsMargins(0, 0, 0, 0);
    layout->setSpacing(0);
    layout->addWidget(m_inspectedClass);
    layout->addWidget(Core::ItemViewFind::createSearchableWrapper(m_treeView));
    m_hierarchyWidget->setLayout(layout);

    m_stackLayout = new QStackedLayout;
    m_stackLayout->addWidget(m_hierarchyWidget);
    m_stackLayout->addWidget(m_infoLabel);
    showNoTypeHierarchyLabel();
    setLayout(m_stackLayout);

    connect(&m_futureWatcher, &QFutureWatcher<void>::finished,
            this, &CppTypeHierarchyWidget::displayHierarchy);

    connect(ProgressManager::instance(), &ProgressManager::taskStarted, [this](Id type) {
        if (type == Constants::TASK_INDEX)
            ++m_runningIndexers;
    });
    connect(ProgressManager::instance(), &ProgressManager::allTasksFinished, [this](Id type) {
        if (type == Constants::TASK_INDEX)
            --m_runningIndexers;
    });
}

void CppTypeHierarchyWidget::perform()
{
    if (m_runningIndexers > 0)
        return;

    if (m_future.isRunning())
        m_future.cancel();

    m_showOldClass = false;

    auto editor = TextEditor::BaseTextEditor::currentTextEditor();
    if (!editor) {
        showNoTypeHierarchyLabel();
        return;
    }

    auto widget = qobject_cast<CppEditorWidget *>(editor->widget());
    if (!widget) {
        showNoTypeHierarchyLabel();
        return;
    }

    showProgress();

    m_future = CppElementEvaluator::asyncExecute(widget);
    m_futureWatcher.setFuture(QFuture<void>(m_future));
    m_synchronizer.addFuture(m_future);

    using namespace std::chrono_literals;
    Core::ProgressManager::addTimedTask(m_futureWatcher.future(),
                                        Tr::tr("Evaluating Type Hierarchy"),
                                        "TypeHierarchy",
                                        2s);
}

void CppTypeHierarchyWidget::performFromExpression(const QString &expression, const FilePath &filePath)
{
    if (m_future.isRunning())
        m_future.cancel();

    m_showOldClass = true;

    showProgress();

    m_future = CppElementEvaluator::asyncExecute(expression, filePath);
    m_futureWatcher.setFuture(QFuture<void>(m_future));
    m_synchronizer.addFuture(m_future);

    Core::ProgressManager::addTask(m_future, Tr::tr("Evaluating Type Hierarchy"), "TypeHierarchy");
}

void CppTypeHierarchyWidget::displayHierarchy()
{
    m_synchronizer.flushFinishedFutures();
    hideProgress();
    clearTypeHierarchy();

    if (!m_future.resultCount() || m_future.isCanceled()) {
        showNoTypeHierarchyLabel();
        return;
    }
    const std::shared_ptr<CppElement> &cppElement = m_future.result();
    if (!cppElement) {
        showNoTypeHierarchyLabel();
        return;
    }
    CppClass *cppClass = cppElement->toCppClass();
    if (!cppClass) {
        showNoTypeHierarchyLabel();
        return;
    }

    m_inspectedClass->setText(cppClass->name);
    m_inspectedClass->setLink(cppClass->link);
    QStandardItem *bases = new QStandardItem(Tr::tr("Bases"));
    m_model->invisibleRootItem()->appendRow(bases);
    QStandardItem *selectedItem1 = buildHierarchy(*cppClass, bases, true, &CppClass::bases);
    QStandardItem *derived = new QStandardItem(Tr::tr("Derived"));
    m_model->invisibleRootItem()->appendRow(derived);
    QStandardItem *selectedItem2 = buildHierarchy(*cppClass, derived, true, &CppClass::derived);
    m_treeView->expandAll();
    m_oldClass = cppClass->qualifiedName;

    QStandardItem *selectedItem = selectedItem1 ? selectedItem1 : selectedItem2;
    if (selectedItem)
        m_treeView->setCurrentIndex(m_model->indexFromItem(selectedItem));

    showTypeHierarchy();
}

QStandardItem *CppTypeHierarchyWidget::buildHierarchy(const CppClass &cppClass, QStandardItem *parent,
                                            bool isRoot, const HierarchyMember member)
{
    QStandardItem *selectedItem = nullptr;
    if (!isRoot) {
        QStandardItem *item = itemForClass(cppClass);
        parent->appendRow(item);
        parent = item;
        if (m_showOldClass && cppClass.qualifiedName == m_oldClass)
            selectedItem = item;
    }

    const QList<CppClass> classes = sortClasses(cppClass.*member);
    for (const CppClass &klass : classes) {
        QStandardItem *item = buildHierarchy(klass, parent, false, member);
        if (!selectedItem)
            selectedItem = item;
    }
    return selectedItem;
}

void CppTypeHierarchyWidget::showNoTypeHierarchyLabel()
{
    m_infoLabel->setText(Tr::tr("No type hierarchy available"));
    m_stackLayout->setCurrentWidget(m_infoLabel);
}

void CppTypeHierarchyWidget::showTypeHierarchy()
{
    m_stackLayout->setCurrentWidget(m_hierarchyWidget);
}

void CppTypeHierarchyWidget::showProgress()
{
    m_infoLabel->setText(Tr::tr("Evaluating type hierarchy..."));
    if (!m_progressIndicator) {
        m_progressIndicator = new ProgressIndicator(ProgressIndicatorSize::Large);
        m_progressIndicator->attachToWidget(this);
    }
    m_progressIndicator->show();
    m_progressIndicator->raise();
}
void CppTypeHierarchyWidget::hideProgress()
{
    if (m_progressIndicator)
        m_progressIndicator->hide();
}

void CppTypeHierarchyWidget::clearTypeHierarchy()
{
    m_inspectedClass->clear();
    m_model->clear();
}

static QString getExpression(const QModelIndex &index)
{
    const QString annotation = index.data(AnnotationRole).toString();
    if (!annotation.isEmpty())
        return annotation;
    return index.data(Qt::DisplayRole).toString();
}

void CppTypeHierarchyWidget::onItemActivated(const QModelIndex &index)
{
    auto link = index.data(LinkRole).value<Link>();
    if (!link.hasValidTarget())
        return;

    const Link updatedLink = CppElementEvaluator::linkFromExpression(
                getExpression(index), link.targetFilePath);
    if (updatedLink.hasValidTarget())
        link = updatedLink;

    Core::EditorManager::openEditorAt(link, Constants::CPPEDITOR_ID);
}

void CppTypeHierarchyWidget::onItemDoubleClicked(const QModelIndex &index)
{
    const auto link = index.data(LinkRole).value<Link>();
    if (link.hasValidTarget())
        performFromExpression(getExpression(index), link.targetFilePath);
}

Qt::DropActions CppTypeHierarchyModel::supportedDragActions() const
{
    // copy & move actions to avoid idiotic behavior of drag and drop:
    // standard item model removes nodes automatically that are
    // dropped anywhere with move action, but we do not want the '+' sign in the
    // drag handle that would appear when only allowing copy action
    return Qt::CopyAction | Qt::MoveAction;
}

QStringList CppTypeHierarchyModel::mimeTypes() const
{
    return DropSupport::mimeTypesForFilePaths();
}

QMimeData *CppTypeHierarchyModel::mimeData(const QModelIndexList &indexes) const
{
    auto data = new DropMimeData;
    data->setOverrideFileDropAction(Qt::CopyAction); // do not remove the item from the model
    for (const QModelIndex &index : indexes) {
        auto link = index.data(LinkRole).value<Link>();
        if (link.hasValidTarget())
            data->addFile(link.targetFilePath, link.targetLine, link.targetColumn);
    }
    return data;
}

// CppTypeHierarchyFactory

class CppTypeHierarchyFactory final : public TextEditor::TypeHierarchyWidgetFactory
{
    TextEditor::TypeHierarchyWidget *createWidget(Core::IEditor *editor) final
    {
        const auto textEditor = qobject_cast<TextEditor::BaseTextEditor *>(editor);
        if (!textEditor)
            return nullptr;
        const auto cppDoc = qobject_cast<CppEditorDocument *>(textEditor->textDocument());
        if (!cppDoc || cppDoc->usesClangd())
            return nullptr;

        return new CppTypeHierarchyWidget;
    }
};

static CppTypeHierarchyFactory &cppTypeHierarchyFactory()
{
    static CppTypeHierarchyFactory theCppTypeHierarchyFactory;
    return theCppTypeHierarchyFactory;
}

void setupCppTypeHierarchy()
{
    (void) cppTypeHierarchyFactory(); // Trigger instantiation
}

} // CppEditor::Internal
